The recovery and recycling of mercury from fluorescent lamps using photocatalytic techniques

BACKGROUND: Release of mercury from fluorescent lamps must be minimized to avoid its hazardous effects on human beings and other living organisms. Because of this, increasing attention is given to the improvement of existing techniques for its recovery as well as the development of new ones. This paper describes the application of heterogeneous photocatalysis for the selective reduction of mercury from fluorescent lamps. The whole process involves mercury chemical extraction using aqueous solutions of sodium hypochlorite. After pH adjustment of the resulting aqueous solution, the photocatalytic reduction of mercury is performed in the presence of titanium dioxide and citric acid as an auxiliary organic agent. RESULTS: Mercury removal from the aqueous solution is higher than 99% and the final residual concentration is 4 ppb. A mixture of different mercury compounds is obtained in solid form deposited on the titanium oxide photocatalyst which can easily be redissolved into a small volume of sodium hypochlorite. Metallic mercury could be obtained from the residual Hg(II) solution by conventional cementation techniques with iron as reducing agent. CONCLUSION: Results show high efficiencies of the photocatalytic technique for recovery and recycling of mercury from fluorescent lamps. Copyright © 2009 Society of Chemical Industry     

Partial nitrification of wastewater from an aminoplastic resin producing factory.

Nitrification via nitrite was studied in two aerobic reactors treating wastewater from an aminoplastic resin producing factory at HRT varying between 1.37-1.89 and 2.45-3.63 days. Both eactors were fed with concentrations of 366, 450, 1099 and 1899 mg N-NH4+/L. In general in the reactor operated at a lower HRT, the nitritation percentage decreased from 87.2 to 21.6%, while the nitratation percentage remained always lower than 2.5% (except in the last period) when the ammonium concentration was increased. This behaviour could be due to the inhibition of the ammonium and nitrite oxidation produced by high free ammonia concentrations up to 179.3 mg N-NH3/L. In the reactor operated at a higher HRT, the nitritation percentage decreased and the nitratation percentage increased from 88.6 to 39.6% and from 0.65 to 35.7%, respectively, due to an increase of the dissolved oxygen concentration from 0.76 to 1.02 mg O2/L. However, when ammonium was fed at a concentration of 1898.7 mg N-NH4+/L, the nitritation increased and the nitratation decreased, probably as a result of the accumulation of free ammonia up to 2.04 mg N-NH3/L, meaning that nitrite oxidizers were inhibited. Nitrite build-up was observed after each modification of ammonium concentration in the feed.     

Experiments with service-oriented architectures for industrial robotic cells programming

Integration of equipment in industrial robot cells is to an increasing part involved with interfacing modern Ethernet technologies and low-cost mass produced devices, such as vision systems, laser cameras, force–torque sensors, soft-PLCs, digital pens, pocket-PCs, etc. This scenario enables integrators to offer powerful and smarter solutions, more adapted to small and medium enterprises (SMEs), capable of integrating process knowledge and interface better with humans. Nevertheless, programming all these devices efficiently requires too much specific knowledge about the devices, their hardware architectures and specific programming languages, details about system communication low-level protocols, and other tricky details at the system level. To address these issues, this paper describes and analyses two of the most interesting service-oriented architectures (SOA) available, which exhibit characteristics that are well adapted to industrial robotics cells. To compare, discuss and evaluate their programming features and applicability a test bed was specially designed, and the two SOA are fully implemented to program the test bed. Special focus is given to the way services are specified and to the orchestration tools used to manage system logic. The obtained results show clearly that using integrations schemes based on SOA reduces system integration time and are more adapted to industrial robotic cell system integrators.     

LOCALIZING THE IRIS THROUGH MEMETIC ALGORITHMS

An iris recognition system requires efficient image processing techniques in order to duly represent and interpret the iris structural characteristics of an individual. The first processing stage should be the identification of the iris region in an eye image. This work introduces the application of evolutionary algorithms to localize the iris region in an eye image. A method based on memetic algorithms was proposed and used to find the circles that represent the external iris border and the pupil border. This method is applied after detecting the edges of the image through gradient algorithms. The efficiency of the memetic algorithm in solving the problem was compared to the application of the Wildes' method, which uses the Circular Hough Transform (CHT), a well-known algorithm employed to find circles in an edged image. To test the algorithms, images from the UBIRIS database (Proença and Alexandre 2005 Proença , H. and L. A. Alexandre . 2005 . UBIRIS: A noisy iris image database . ICIAP 2005, 13th Int. Conf. on Image Analysis and Processing , Cagliari, Ital. Lect. Notes Comput. Sci. 3617 : 970 – 977 . [Google Scholar]) were used.     

Integration schemes for von‐Mises plasticity models based on exponential maps: numerical investigations and theoretical considerations

We consider three different exponential map algorithms for associative von‐Mises plasticity with linear isotropic and kinematic hardening. The first scheme is based on a different formulation of the time continuous plasticity model, which automatically grants the yield consistency of the method in the numerical solution. The second one is the quadratically accurate but non‐yield consistent method already proposed in Auricchio and Beirão da Veiga (Int. J. Numer. Meth. Engng 2003; 56 : 1375–1396). The third method is an improved version of the second one, in which the yield consistency condition is enforced a posteriori. We also compare the performance of the three methods with the classical radial return map algorithm. We develop extensive numerical tests which clearly show the main advantages and disadvantages of the three methods. Copyright © 2005 John Wiley & Sons, Ltd.     

Bioprocesses for air pollution control

Bioprocesses have been developed as relatively recent alternatives to conventional, non‐biological technologies, for waste gas treatment and air pollution control in general. This paper reviews major biodegradation processes relevant in this field as well as both accepted and major innovative bioreactor configurations studied or used nowadays for the treatment of polluted air, i.e. biofilters, one‐ and two‐liquid phase biotrickling filters, bioscrubbers, membrane bioreactors, rotating biodiscs and biodrums, one‐ and two‐liquid phase suspended growth bioreactors, as well as hybrid reactor configurations. Some of these bioreactors are being used at full‐scale for solving air pollution problems, while others are still at the research and development stage at laboratory‐ or pilot‐scale. Copyright © 2009 Society of Chemical Industry     

Extramedullary anaplastic plasmacytoma

A case of extramedullary plasmacytoma of the maxillary sinus, locally aggressive, in a 65 years old man is presented. Clinical diagnosis of adenocarcinoma was suspected but the pathological study showed an anaplastic morphology, with little plasmacytic differentiation and lack of stain with cytokeratins and epithelial membrane antigen (EMA), immunohistochemical marker of plasmatic cells, among others. Definitive diagnosis was based on light chain restriction and lack of multiple myeloma.     

The influence of diluent on the release of theophylline from hydrophilic matrix tablets

The role of β-cyclodextrin (β-CD) on the apparent solubility of theophylline was investigated by the solubility method. Binary systems of theophylline and β-CD were prepared using the dry co-grinding method. Their characterization was performed by differential scanning calorimetry (DSC). The dissolution rate of theophylline and theophylline/β-CD and dissolution studies of matrix tablets prepared from mixtures containing theophylline and ground theophylline were carried out. It can be concluded that β-CD is related to an increase in the apparent solubility and dissolution rate of the drug, promoting improvement on the release of theophylline from matrices manufactured with hydroxypropylmethylcellulose (HPMC). This can be attributed to the amorphous state and the increased wettability of the drug.     

Explaining sex differences in managerial career satisfier preferences: The role of gender self-schema.

Using survey data from 400 managers, the authors examined whether gender self-schema would explain sex differences in preferences for status-based and socioemotional career satisfiers. Female gender self-schema, represented by femininity and family role salience, completely mediated the relationship between managers' sex and preferences for socioemotional career satisfiers. However, male gender self-schema, represented by masculinity and career role salience, did not mediate the relationship between managers' sex and preferences for status-based career satisfiers. As expected, male managers regarded status-based career satisfiers as more important and socioemotional career satisfiers as less important than female managers did. The proposed conceptualization of male and female gender self-schemas, which was supported by the data, enhances understanding of adult self-schema and work-related attitudes and behavior. (PsycINFO Database Record (c) 2011 APA, all rights reserved)